Titanic Acid Solid Electrolyte with Cation Substitution for Li-Ion Stability
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Solution Overview
Problem
Conventional oxide-based solid electrolyte materials for lithium-ion secondary batteries face issues with hydrogen sulfide production, high production costs due to rare earth usage, and insufficient electrochemical stability, while sulfide-based materials have safety concerns with moisture reactivity.
Innovation Solution
A titanic acid-based solid electrolyte material with a layered structure, where lithium ions and divalent or higher-valent cations are intercalated between host layers, and titanium sites are partially substituted by monovalent to trivalent cations, eliminating the risk of hydrogen sulfide production and rare earth usage, enhancing electrochemical stability and lithium-ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based solid electrolyte materials are used to improve safety compared to liquid electrolytes, then safety is improved, but electrochemical stability is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by using a titanic acid-based structure with specific cation substitutions (monovalent to trivalent cations at titanium sites) and intercalated lithium ions with divalent or higher-valent cations. This compositional parameter change achieves both improved electrochemical stability and maintained safety compared to conventional oxide-based materials.
Solution Approach 2:
The patent creates a composite solid electrolyte material by combining titanic acid-based host structure with multiple types of cations (lithium ions, divalent or higher-valent cations, and monovalent to trivalent cations for substitution). This composite approach achieves superior electrochemical stability while maintaining the safety benefits of solid electrolytes.
2Reliability
If sulfur is doped into oxide-based solid electrolyte materials to improve lithium-ion conductivity, then lithium-ion conductivity is improved, but hydrogen sulfide production risk increases
Solution Approach 1:
The patent extracts and eliminates sulfur from the solid electrolyte composition entirely, replacing it with a titanic acid-based structure. This removes the source of hydrogen sulfide production while maintaining high lithium-ion conductivity through the titanic acid structure and cation intercalation/substitution mechanism.
Solution Approach 2:
The patent replaces expensive and problematic sulfur doping with a more stable titanic acid-based structure that does not require continuous sulfur addition or special handling, achieving sustained high conductivity without hydrogen sulfide generation.
3Stability of the object's composition
If rare earth elements are used in oxide-based solid electrolyte materials to improve performance, then electrochemical stability is improved, but production cost increases
Solution Approach 1:
The patent replaces expensive rare earth elements with a titanic acid-based structure using common cations (lithium, and divalent or higher-valent cations such as calcium, strontium, barium, or trivalent cations such as aluminum). This significantly reduces production cost while achieving comparable or superior electrochemical stability.
Solution Approach 2:
The patent changes the elemental composition parameters from rare earth-containing oxides to titanic acid-based structures with common cations, achieving the same electrochemical stability function through different, more cost-effective chemical parameters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The titanic acid-based solid electrolyte material provides a safe, cost-effective, and high-power lithium-ion secondary battery with improved electrochemical stability and lithium-ion conductivity, free from hydrogen sulfide risks and rare earth dependencies.
Implementation Method 1
lithium ions and divalent or higher-valent cations (α) are intercalated in interlayers between the host layers
Implementation Method 2
titanium sites in the host layers being partially substituted by monovalent to trivalent cations (β)
Data Source
AI summary
Provided is a titanic acid-based solid electrolyte material free from risk of production of hydrogen sulfide, free of rare earth, and having good electrochemical stability and lithium-ion conductivity. A titanic acid-based solid electrolyte material 1 is made of a titanate having a structure in which a plurality of host layers 2 are laid one on top of another, the host layer 2 being formed so that octahedra each formed of a titanium atom coordinated with six oxygen atoms are two-dimensionally chained while sharing ridges, and lithium ions 3 and divalent or higher-valent cations (α) 4 are intercalated in interlayers between the host layers 2, titanium sites in the host layers 2 being partially substituted by monovalent to trivalent cations (β).